1. Field of the Invention
The present invention relates to a water spouting device that can discharge air bubble entrained water.
2. Description of the Related Art
Water spouting devices have been proposed which entrain air bubbles into spouted water to discharge the resultant air bubble entrained water in order to diminish the sound of the water splashing onto a sink or a lavatory bowl to which the water is to be spouted or to suppress splash-back of the water from the sink or the lavatory bowl. In particular, in recent years, a water spouting device has been proposed which starts to increase the entrainment rate of air bubbles at a low flow rate stage with a low flow velocity in order to improve the feeling of massiveness of water, as described in Japanese Patent Laid-Open No. 2002-275969.
The water spouting device in Japanese Patent Laid-Open No. 2002-275969 includes a bubbly water spouting member installed at the tip of a spout of a water faucet via a joint, the bubbly water spouting member including an air entraining mechanism and a rectification mechanism provided in this order from an upstream side in the middle of a channel extending between an inflow port and the discharge port. The air entrainment mechanism includes a pressure reducing plate, a channel surrounding wall formed downstream of the pressure reducing plate, and a backflow preventing portion formed downstream of the channel surrounding wall. The pressure reducing plate includes a plurality of small holes disposed on the circumference of a circle which is concentric with the discharge port and larger than the discharge port in diameter. The pressure reducing plate is disposed so as to close the channel. Air holes are formed in the channel surrounding wall located downstream of the pressure reducing plate. The backflow preventing portion is disposed downstream of an area in which the air holes are formed. The rectification mechanism includes an inclined portion, a rectification portion, a rectification grid, and a rectification path. The inclined portion includes a channel with a diameter decreasing such that the channel is shaped like a funnel downstream of the backflow preventing portion. The rectification portion includes a channel which is concentric with the discharge port and which extends from a downstream end of the inclined portion toward the discharge port. The rectification grid is a grid-like portion of the channel disposed so as to close the rectification portion. The rectification path is a channel connected to the rectification portion downstream of the rectification grid. Moreover, a throttling portion with a smaller channel cross section than that of the joint is provided upstream of the pressure reducing plate.
The water spouting device described in Japanese Patent Laid-Open No. 2002-275969 is configured as described above. Thus, when cleaning water passes through the small holes in the pressure reducing plate, pressure energy is converted into kinetic energy to increase the flow velocity of jet flows from the small holes. The jet flows are entrained with surrounding air because of the viscosity thereof. Water flows generated with the air entrained therein grow into high-speed water flows with relatively large air bubbles, which then collide against the funnel-like inclined portion. The high-speed water flows having collided against the inclined portion become turbulent. Hence, the relatively large air bubbles contained in the high-speed water flows are broken to convert the high-speed water flows into water flows with fine air bubbles entrained therein. The water flows with the air bubbles entrained therein converge along the inclined portion and are rectified by the rectification grid. The water flows are thus integrated together, and the resultant water flow is discharged from the discharge port.
The water spouting device described in Japanese Patent Laid-Open No. 2002-275969 exerts what is called en ejector effect to generate air bubble entrained water. Thus, at a low flow rate stage, the water spouting device can effectively generate water entrained with fine air bubbles to discharge the resultant air bubble entrained water to a sink or a lavatory bowl from the discharge port.
When air bubble entrained water is generated based on the ejector effect, the generation depends on the effect of entraining air into the water as a result of an increase in the flow velocity of the jet flows from the small holes in the pressure reducing plate. Thus, as the water amount and thus the flow velocity increases, the amount of air entrained in the water in the form of air bubbles tends to increase consistently with the flow velocity. Thus, even when the process shifts to a high flow rate stage with a high flow velocity, water with a high entrainment rate of air bubbles is generated and discharged.
At the low flow rate stage, an increase in the entrainment rate of air bubbles entrained in the water allows the feeling of massiveness of spouted water to be improved and contributes to water saving without failing to meet the basic purpose of diminishing the sound of the water splashing onto the sink or lavatory bowl to which the water is to be spouted or suppressing splash-back of the water from the sink or the lavatory bowl. Thus, the arrangement and shapes of members of the water spouting device are designed so as to increase the entrainment rate of air bubbles at the low flow rate stage as much as possible.
However, in actual use, water needs to be supplied not only at such a low flow rate as described but also at a high flow rate. For example, if a glass or a vase is to be filled with water, the amount of water supplied may need to be increased in order to fill the glass or the vase quickly. In the water spouting device described in Japanese Patent Laid-Open No. 2002-275969, an increased flow rate increases the entrainment rate of air bubbles. Thus, under the effect of an increase in the total amount of water resulting from an increased entrainment rate of air bubbles and exceeding the user's intended increase in water amount, air bubble entrained water is discharged at a high flow rate that exceeds a value corresponding to the user's expected feeling. In particular, as more effort is made to design the arrangement and shapes of the members so as to increase the entrainment rate of air bubbles at the low flow rate stage, the above-described phenomenon appears more notably at the high flow rate stage.
If water is used to wash eating utensils or the hands, provided that spouted water gives the appropriate feeling of massiveness and that the washing capability is unchanged, the use of water spouted at a low flow rate is preferable in terms of both the practical use and water saving, and users are expected to use such water spouted at the low flow rate. However, if a glass or a vase is to be filled with water, the user desires to fill the glass or the vase quickly, and thus naturally operates the water spouting device so that the water flows at a high flow rate.
As described above, when the user operates the water spouting device in accordance with the user's feeling so that the water flows at a high flow rate, and as a result, air bubble entrained water is discharged which has such a total amount (corresponding to the actual amounts of water and air bubbles) as makes the user feel that the resultant amount of water significantly exceeds that intended by the user, the feeling of massiveness of spouted water is definitely improved but the following adverse effect may be exerted. Even though an attempt is made to fill the glass or the vase with water, the water overflows the glass or the valve because of a return flow resulting from the high intensity of the water flow. As a result, the glass or the vase may be filled only to half of the volume thereof. Moreover, even when the glass or the vase is to be filled to half of the volume thereof, air bubble entrained water which is in actuality increased in amount by the air bubbles is poured into the glass or the vase. Thus, even with the user's recognition that the glass or the vase has been filled to half of the volume thereof, the glass or the vase may have actually been filled only with a smaller amount of water. Furthermore, in cases other than that where the glass or the vase is filled with water, the water spouting device may fail to meet the basic purpose of diminishing the sound of water splashing onto the sink or lavatory bowl to which the water is to be spouted or suppressing splash-back of the water from the sink or the lavatory.
If the user needs to more precisely adjust the amount of spouted water in order to avoid the above-described problems, the corresponding operation is cumbersome and involves the user's delicate feeling. This may significantly degrade the usability. Furthermore, the following method is possible. The user manually adjusts the opening of the air holes depending on an increase in the amount of water spouted; the user increases the entrainment rate of air bubbles at a low flow rate, while suppressing the entrainment rate of air bubbles at a high flow rate. However, this method is also cumbersome and time-consuming for the user and offers very inferior usability in a practical sense.
The present invention has been developed in view of the above-described problems. An object of the present invention is to provide a water spouting device which enables air bubble entrained water with an increased entrainment rate of air bubbles to be discharged at the low flow rate stage even though the user adjusts the flow rate based on the same feeling as that for the conventional water spouting device, the present water spouting device further enabling, at the high flow rate stage, prevention of discharge of air bubble entrained water with such a total amount as makes the user feel that the resultant amount of water significantly exceeds that intended by the user.